Phytochemical properties and hypotensive mechanism of extracts from Gardenia jasminoides seeds.

An improved extraction method was used to obtain hypotensive principles from seeds of Gardenia jasminoides Ellis (Rubiaceae). The crude extract contained mainly glycosides and had minimal direct cardiac depressant effects. The hypotensive action was attributable to a reflex phenomenon, involving both the parasympathetic and the sympathetic vasomotor centers. It was shown that the hypotensive and bradycardiac properties of Gardenia extract were entirely abolished in a tropinized and vagotomized rats, but only partially attenuated in carotid sinus denervated rats, and that low cervical spinal transection in rats did not inhibit the hypotensive responses. Accordingly, the afferent limb of this cardiovascular reflex are consisted of both vagus nerves and baroreceptor afferents, whereas the vagi alone constituted the efferent limb.